At the present time, agricultural mowing machines and lawn mowers are substantially of two widely used types, namely principally free-cutting rotary mowing machines and to a lesser extent, beam mowers.
Rotary mowing machines, the principle of which is also applied to many lawn mowers, work with very high peripheral speeds Of the cutters fastened on the outside of a rotor. These speeds amount to about 40 to 80 meters per second, so that enormous centrifugal forces are produced. If foreign bodies, for example stones, come into the range of action of the cutters and are thrown off, there is a serious risk to animals and people.
With beam mowers problems arise through friction between the stationary and moving parts of the mowing system, particularly through the penetration of sand, dirt or plant sap into the zone between the two parts. This results in high energy consumption, even during idling. In addition, the cutters must be regularly reground.
Since rotating rotary mowing machines and lawn mowers have a relatively high power consumption because of the high peripheral speeds, only two types of drive are available for known types of mowing machines and lawn mowers, namely either an electric motor connected to the mains or a petrol or diesel engine, the engine being used either as a direct drive, as in the conventional lawn mower, or as an indirect drive via the so-called power take-off shaft of a tractor for agricultural machines. In the case of the electric motor the autonomy of the mower is restricted by the length of the power cable and there is a danger that the cable will become caught in the mower. In the case of the petrol engine, the noise and exhaust gases are a nuisance, so that the use of such mowers is increasingly controlled by regulations. Thus, for example, in some countries noise emission is already limited by law.
In the case of agricultural applications the relatively high weight of mowing machines and their tractors is an additional disadvantage, since it is well known to lead to extremely undesirable soil compaction.